Commit | Line | Data |
---|---|---|
06cec913 GM |
1 | ;;; hex-util.el --- Functions to encode/decode hexadecimal string. |
2 | ||
3 | ;; Copyright (C) 1999, 2001, 2002, 2003, 2004, | |
e3fe4da0 | 4 | ;; 2005, 2006, 2007, 2008 Free Software Foundation, Inc. |
06cec913 GM |
5 | |
6 | ;; Author: Shuhei KOBAYASHI <shuhei@aqua.ocn.ne.jp> | |
7 | ;; Keywords: data | |
8 | ||
9 | ;; This file is part of GNU Emacs. | |
10 | ||
eb3fa2cf | 11 | ;; GNU Emacs is free software: you can redistribute it and/or modify |
06cec913 | 12 | ;; it under the terms of the GNU General Public License as published by |
eb3fa2cf GM |
13 | ;; the Free Software Foundation, either version 3 of the License, or |
14 | ;; (at your option) any later version. | |
06cec913 GM |
15 | |
16 | ;; GNU Emacs is distributed in the hope that it will be useful, | |
17 | ;; but WITHOUT ANY WARRANTY; without even the implied warranty of | |
18 | ;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the | |
19 | ;; GNU General Public License for more details. | |
20 | ||
21 | ;; You should have received a copy of the GNU General Public License | |
eb3fa2cf | 22 | ;; along with GNU Emacs. If not, see <http://www.gnu.org/licenses/>. |
06cec913 GM |
23 | |
24 | ;;; Commentary: | |
25 | ||
26 | ;;; Code: | |
27 | ||
28 | (eval-when-compile | |
29 | (defmacro hex-char-to-num (chr) | |
30 | `(let ((chr ,chr)) | |
31 | (cond | |
32 | ((and (<= ?a chr)(<= chr ?f)) (+ (- chr ?a) 10)) | |
33 | ((and (<= ?A chr)(<= chr ?F)) (+ (- chr ?A) 10)) | |
34 | ((and (<= ?0 chr)(<= chr ?9)) (- chr ?0)) | |
35 | (t (error "Invalid hexadecimal digit `%c'" chr))))) | |
36 | (defmacro num-to-hex-char (num) | |
37 | `(aref "0123456789abcdef" ,num))) | |
38 | ||
39 | (defun decode-hex-string (string) | |
40 | "Decode hexadecimal STRING to octet string." | |
41 | (let* ((len (length string)) | |
42 | (dst (make-string (/ len 2) 0)) | |
43 | (idx 0)(pos 0)) | |
44 | (while (< pos len) | |
45 | ;; logior and lsh are not byte-coded. | |
46 | ;; (aset dst idx (logior (lsh (hex-char-to-num (aref string pos)) 4) | |
47 | ;; (hex-char-to-num (aref string (1+ pos))))) | |
48 | (aset dst idx (+ (* (hex-char-to-num (aref string pos)) 16) | |
49 | (hex-char-to-num (aref string (1+ pos))))) | |
50 | (setq idx (1+ idx) | |
51 | pos (+ 2 pos))) | |
52 | dst)) | |
53 | ||
54 | (defun encode-hex-string (string) | |
55 | "Encode octet STRING to hexadecimal string." | |
56 | (let* ((len (length string)) | |
57 | (dst (make-string (* len 2) 0)) | |
58 | (idx 0)(pos 0)) | |
59 | (while (< pos len) | |
60 | ;; logand and lsh are not byte-coded. | |
61 | ;; (aset dst idx (num-to-hex-char (logand (lsh (aref string pos) -4) 15))) | |
62 | (aset dst idx (num-to-hex-char (/ (aref string pos) 16))) | |
63 | (setq idx (1+ idx)) | |
64 | ;; (aset dst idx (num-to-hex-char (logand (aref string pos) 15))) | |
65 | (aset dst idx (num-to-hex-char (% (aref string pos) 16))) | |
66 | (setq idx (1+ idx) | |
67 | pos (1+ pos))) | |
68 | dst)) | |
69 | ||
70 | (provide 'hex-util) | |
71 | ||
72 | ;; arch-tag: fe8aaa79-6c86-400e-813f-5a8cc4cb3859 | |
73 | ;;; hex-util.el ends here |